This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
An internal combustion engine creates force by burning fuel and air. In general, internal combustion engines or “engines” have two assemblies—the engine head and the engine block. The head of conventional engines typically includes an intake valve that opens and closes an intake port and an exhaust value that opens and closes an exhaust port. The block of conventional engines generally includes a crankshaft which is turned by a piston as the piston moves up and down in a cylinder that connects the engine head and block. In operation, the intake valve opens to allow a fuel and air mixture to enter an explosion chamber in the cylinder with a piston forming the floor of the chamber. An explosion of the fuel and air is created by a spark from a spark plug. This explosion causes the piston in the chamber to move downward and rotate the crankshaft in the engine block. The exhaust value opens and allows the exhaust from the explosion to escape as the piston returns to its position in the chamber before the explosion, helping to push the exhaust through the exhaust valve.
The block of the engine and the housing of the crankshaft are usually assembled in one casting. The camshaft, which operates the valves, can be located in the head or the block. In engines cooled with water, the head and the block of the engine have ducts for the cooling water. Generally, the pistons are connected by piston rods with the crankshaft that is rotating. The crankshaft has a fixed location to ensure uniformity of the rotation of the engine. The bottom of the engine at the lower end of the housing of the crankshaft serves for the placement of oil for lubrication.
Many different types of combustion engines have been developed. For example, an Otto engine utilizes a four-stroke approach (known as the Otto cycle in honor of Nikolaus Otto, who invented it in 1867). The Otto engine prepares fuel and air for burning outside of the cylinder using a carburetor, which mixes the correct amount of fuel and air. Another type of engine is a diesel engine (also named after its inventor, Rudolf Diesel). Diesel engines do not have spark plugs, rather a diesel engine compresses air and injects fuel into the compressed air. The heat of the compressed air lights the fuel spontaneously. A third type of engine is the Wankel engine or Wankel rotary engine (named after Felix Wankel). Instead of moving a piston up and down, the Wankel engine rotates a triangular rotor. The force to move the rotor comes from a combustion of fuel and air contained in a chamber formed by part of the housing and one face of the triangular rotor.
Modern engines can also be classified by how the fuel and air are provided and the exhaust is removed. A “four-stroke engine” has two valves for each cylinder—a suction valve and an exhaust valve. During the first stroke, the piston moves from an upper portion of the cylinder towards the bottom. The increased space in the cylinder (from the movement of the piston) creates a force that pushes the fuel and air mixture out of the carburetor into the explosion chamber. During the second stroke, the piston moves from the bottom portion of the cylinder towards the top. The piston compresses the fuel and air mixture in the cylinder because the valves are closed. In the third stroke, the mixture is ignited by a spark in the spark plug. The mixture burns, increasing the temperature and the pressure. This pressure from the burning process pushes the piston from the upper to the lower portion of the cylinder, exerting a force to rotate the crankshaft. In the fourth stroke, the burned gases are exhausted out through an opened exhaust valve. The piston moves from the bottom towards the upper portion of the cylinder, pushing the remnants of burned gasses from the cylinder. The process then repeats itself.
In a “two-stroke engine,” the filling and emptying of the cylinder happens during one part of the rotation of the crankshaft. Instead of suction and exhaust valves, the two-stroke engine has openings on the cylinder liner which are closed and opened by movement of the piston. Typically, the exhaust opening is located closer to the top of the cylinder than the intake opening. When the piston is moving up it creates pressure to push exhaust out the exhaust opening. Before the piston reaches the top of its movement in the cylinder, it covers over the exhaust creating pressure in the explosion chamber for the combustion to occur. When the piston is moving down, it uncovers the intake opening and acts as a pump to move the fuel and air mixture into the chamber.
Engines can also be categorized according to the position of the cylinders. Examples of engines with cylinders located in different positions are sequence or “in-line” engines, V-engines, rotation engines, and boxer engines. Sequence engine cylinders are placed one cylinder after another in a row. As a result, working strokes overlap, ensuring uniformity in the drive of the crankshaft. V-engine cylinders are placed in two lines set at an angle to each other. Thus, crankshafts for V-engines can be shorter than those for sequence engines. As discussed above, rotation engines, like the Wankel engine, do not have pistons that move in up-and-down fashion; rather the pistons are rotors formed in the shape of a triangle. In the first stroke of a rotation engine, the rotor rotates to open the intake opening, which allows a fuel and air mixture to enter a chamber. As the rotor rotates in a second stroke, the volume of the chamber decreases and the mixture is compressed. In a third stroke, a spark from the spark plug ignites the mixture. Burned gasses are spread and set the rotor in motion. The volume of the chamber again increases. In a fourth stroke, the first gasket of the chamber slides ahead along the exhaustion opening, opening it for the burned gasses to escape.
Boxer engine cylinders are flat in that they are located 180 degrees from each other. The crankshaft can be shorter than the crankshaft of the sequence engine, and in four cylinder engines, boxer engines only need three standing bearings. In a boxer engine with four cylinders, there is ignition on each half rotation of the crankshaft. Boxer engines are characterized by uniform flow of the rotary momentum, enabling a quiet workflow, because movement on one side of the engine levels with the movement on the other side.
Despite various advancements that have been made heretofore in engine technology, it would be desirable to improve conventional engines, such as the engines described above. For example, it would be desirable to reduce the sound volume produced by engines and to reduce the consumption of fuel needed. Moreover, it would be desirable to produce high power engines with a wide range of uses. Yet still further, it would be desirable to increase the engine's power and momentum.